Matthew Yglesias on what should be common sense:
…the idea that labor union objections to firing their members are fundamentally about evaluation metrics is extraordinarily naive. Under any possible evaluation scheme—whether for teachers, journalists, auto workers, basketball players, truck drivers, or what have you—the union is going to want to make it as difficult as possible to fire people. The idea of a labor union is to, among other things, represent the workforce’s interests and give voice to its desires. And in my experience people don’t want to get fired! In any kind of unionized workplace you see management pushing for more flexibility (i.e., ability to fire people) and the union pushing for more job securitiy (i.e., it’s easier to keep your job even if management decides you’re bad at it).